Early Years Of Operation Research Articles

An Improved Method for the Recognition of Seismic Families: Application to the Garfagnana-Lunigiana Area, Italy

With the aim to find a more objective way to detect seismic families, we applied a series of successive steps to constrain the results of a waveform similarity analysis. The evaluation of similarity was carried out on the waveforms recorded in the period 1999–2003 by the stations operating in the Garfagnana area, located in northern Tuscany (Italy). The algorithm is based on the cross-correlation technique applied in a process that overcomes the limit of one order of magnitude between events to be compared through a bridging technique. In practice, if two couples of events (A, B) and (B, C), each exceeding the correlation threshold, share a common quake (B), then all three events are attributed to the same family even if the match between A and C is below a value chosen as a reference for similarity. To avoid any subjective choice of threshold for cross-correlation values, the results from the computation algorithm are submitted to a routine that gives increasing reliability to them if they are confirmed by the three components of the seismogram and if the number of families detected by each station is confirmed by more recordings. This latter constraint is made possible by the geometry of the recording network, with interdistances between stations of the order of 40–50 km. The process finally leads to the recognition of 27 families detected and confirmed by, on average, 3 stations that represent 40% of the recording capabilities. Since the performances of the recording network have been very odd in the past, especially in the early years of operation, the reliability of the detection is much higher, as in most cases the stations that detected the families were the only ones to be effectively recording. The methodology proved to be more efficient than other methods applied in the past; moreover, the results could be probably improved even more if, instead of doing a one-run process, it would be borne as a trial-and-error approach.

Predictors of Low Cardiac Output Syndrome After Isolated Aortic Valve Surgery

Low cardiac output syndrome (LCOS), defined as the need for postoperative intraaortic balloon pump or inotropic support for >30 minutes in the intensive care unit, remains a relatively common complication of aortic valve (AV) surgery. The aim of this study is to identify the preoperative predictors of LCOS in patients undergoing isolated AV surgery. We conducted a retrospective review of data prospectively entered into an institutional database. Between 1990 and 2003, 2255 patients underwent isolated AV surgery with no other concomitant cardiac surgery. The independent predictors of LCOS and operative mortality (OM) were determined by stepwise logistic regression analysis. The overall prevalence of LCOS was 3.9%. The independent predictors of LCOS were (odds ratio in parentheses) renal failure (5.0), earlier year of operation (4.4), left ventricular ejection fraction <40% (3.6), shock (3.2), female gender (2.8), and increasing age (1.02). Overall OM was 2.9%. The OM was higher in patients who experienced LCOS (38% versus 1.5%; P<0.001). The independent predictors of mortality were (odds ratio in parentheses) preoperative renal failure (8.3), urgency of surgery (3.4), previous stroke (2.9), congestive heart failure (2.6), previous cardiac surgery (2.3), hypertension (1.7), and small AV size (1.3). Low-output syndrome is associated with significantly increased morbidity and mortality. Novel strategies to preserve renal function, optimization of preexisting heart failure symptoms, and avoidance of prosthesis-patient mismatch may reduce the incidence of LCOS and lead to improved results after AV surgery.

Non-destructive evaluation of coatings for land-based gas turbines using a multi-frequency eddy current technique

To provide a commercial return from Combined Cycle Gas Turbine (CCGT) technology for power generation, a balance has to be struck between efficiency, maintenance costs and component life. The parts that significantly influence this are collectively known as Hot Gas Path (HGP) components and generally consist of blades, vanes and heat shields. To achieve high thermal efficiencies, these components are subject to high temperatures, centripetal forces and erosive/corrosive atmospheres and therefore need to be protected by complex coatings and through internal cooling. The drive for higher efficiencies, however, often means that the protection put in place is only a partial solution and experience shows that these components have a relatively short lifespan and require regular inspection. Inspections to date have consisted of visual examination and fluorescent penetrant inspections and, therefore, are limited to the detection of surface damage usually associated with 'teething'problems during early years of operation; and are often inadequate for detecting in-service degradation or for coating qualification. Furthermore, as CCGT technology is becoming more established, there is a requirement to assess the remnant life of components of which there is currently no suitable technique. This paper describes the inspection technique developed using a multi-frequency eddy current instrument capable of distinguishing between coatings and substrates for the thickness gauging of TBCs to help qualify coatings prior to engine runs. This is a crucial inspection as poor control during coating application can lead to premature failure of the component by thermo-mechanical fatigue, as was the case at a UK CCGT power station. Here, several blades in one particular row which were coated by two different vendors exhibited TMF cracking, however through a thorough investigation with a multi-frequency instrument, it was possible to identify the poorly coated blades and establish that they were all from the single vendor.

Midterm results of endovascular repair of descending thoracic aortic aneurysms with first-generation stent grafts

Objective Five years after reporting our initial stent-graft repair of descending thoracic aortic aneurysms experience, we determined the 5- to 10-year results of stent-graft treatment and identified risk factors for adverse late outcomes. Methods Between 1992 and 1997, 103 patients (mean age 69 ± 12 years) underwent repair using first-generation (custom-fabricated) stent grafts. Sixty-two patients (60%) were unsuitable candidates for conventional open surgical repair (“inoperable”). Follow-up was 100% complete (mean 4.5 ± 2.5 years; maximum 10 years). Outcome variables included death and treatment failure (endoleak, aortic rupture, reintervention, and/or aortic-related or sudden death). Results Overall actuarial survival was 82% ± 4%, 49% ± 5%, and 27% ± 6% at 1, 5, and 8 years. Survival in open surgical candidates was 93% ± 4% and 78% ± 6% and at 1 and 5 years compared with 74% ± 6% and 31% ± 6% in those deemed inoperable ( P < .001). Independent risk factors for death were older age (hazard ratio = 1.1; P = .008), previous stroke (hazard ratio = 2.8; P = .003), and being designated an inoperable candidate (hazard ratio = 1.9; P = .04). Actuarial freedom from aortic reintervention and treatment failure at 8 years was 70% ± 6% and 39% ± 8%, respectively. Earlier operative year (hazard ratio = 1.2; P = .07), larger distal landing zone diameter (hazard ratio = 1.1; P = .001), and transposition of the left subclavian artery (hazard ratio = 3.3; P = .008) were determinants of treatment failure. Conclusions Survival after aneurysm repair using crude, first-generation stent grafts was satisfactory in good operative candidates but bleak in the inoperable cohort, raising the question of whether asymptomatic patients should have even been treated. Late aortic complications were detected in many patients, reemphasizing the importance of serial imaging surveillance.

Air pollution and lung cancer mortality in the vicinity of a nonferrous metal smelter in Sweden

To evaluate the importance of exposure to ambient air pollution for lung cancer risk, we conducted a case-control study in the vicinity of a nonferrous metal smelter. The smelter started operations in 1930 and had very high emissions during the early decades, particularly of arsenic and SO(2). Among subjects deceased 1961-1990 in the municipality where the smelter is located and who had not worked at the smelter, 209 male and 107 female lung cancer cases were identified and matched by sex and year of birth to 518 and 209 controls, respectively. Information on smoking habits, occupations and residences was collected by questionnaire to next-of-kin and from registry data. Living close to the smelter was associated with a relative risk (RR) for lung cancer of 1.38 [95% confidence interval (CI) 0.89-2.14] among men, adjusted for smoking and occupational exposures. No clear difference in risk was detected for men deceased 1961-1979 compared to men deceased 1980-1990 (RR point estimates 1.42 and 1.29, respectively). There appeared to be an increased risk especially for men exposed in the beginning of the operations (RR = 1.51, 95% CI 0.90-2.54), in particular combined with exposure duration shorter than 20 years (RR = 2.52, 95% CI 0.89-7.11). For women, however, no overall increased risk for lung cancer was observed. Although not significant, our findings thus indicated an increased risk of lung cancer among men living close to the nonferrous smelter. This increase appeared to concern primarily men exposed during the early years of operations, when emissions were very high.

Cancer mortality in a Texas county with prior uranium mining and millingactivities, 1950–2001

Uranium was discovered in Karnes County, Texas, in 1954 and the first uraniummill began operating in 1961 near Falls City. Uranium milling and surface and insitu mining continued in Karnes County until the early 1990s. Remediation ofuranium tailings ponds was completed in the 1990s. There were threemills and over 40 mines operating in Karnes County over these years andpotential exposure to the population was from possible environmentalreleases into the air and ground water. From time to time concerns havebeen raised in Karnes County about potential increased cancer risk fromthese uranium mining and milling activities. To evaluate the possibilityof increased cancer deaths associated with these uranium operations, amortality survey was conducted. The numbers and rates of cancer deaths weredetermined for Karnes County and for comparison for four ‘control’ counties inthe same region with similar age, race, urbanisation and socioeconomicdistributions reported in the 1990 US Census. Comparisons were also made withUS and Texas general population rates. Following similar methods tothose used by the National Cancer Institute, standardised mortality ratios(SMRs) were computed as the ratio of observed numbers of cancers in thestudy and control counties compared to the expected number derived fromgeneral population rates for the United States. Relative risks (RRs) werecomputed as the ratios of the SMRs for the study and the control counties.Overall, 1223 cancer deaths occurred in the population residing in KarnesCounty from 1950 to 2001 compared with 1392 expected based on generalpopulation rates for the US. There were 3857 cancer deaths in the fourcontrol counties during the same 52 year period compared with 4389expected. There was no difference between the total cancer mortality ratesin Karnes County and those in the control counties (RR = 1.0;95% confidence interval 0.9–1.1). There were no significant increases in KarnesCounty for any cancer when comparisons were made with either the USpopulation, the State of Texas or the control counties. In particular, deaths due tocancers of the lung, bone, liver and kidney were not more frequent in KarnesCounty than in the control counties. These are the cancers of a priori interestgiven that uranium might be expected to concentrate more in these tissues thanin others. Further, any radium intake would deposit primarily in the bone andradon progeny primarily in the lung. Deaths from all cancers combined alsowere not increased in Karnes County and the RRs of cancer mortality inKarnes County before and in the early years of operations (1950–64),shortly after the uranium activities began (1965–79) and in two latertime periods (1980–89, 1990–2001) were similar, 1.0, 0.9, 1.1 and 1.0,respectively. No unusual patterns of cancer mortality could be seen in KarnesCounty over a period of 50 years, suggesting that the uranium miningand milling operations had not increased cancer rates among residents.

Assessment and characterization of polychlorinated biphenyls near a hazardous waste incinerator: Analysis of vegetation, snow, and sediments

Samples of spruce needles, snowpack, and sediment were analyzed in the area around the Alberta Special Waste Treatment Centre (ASWTC) near Swan Hills, Canada, in 1997 and 1998, following a major accidental release of polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) in October 1996. The PCB concentrations in spruce needles and snow were mostly elevated to the east of the plant and contained congeners that were not present at upwind or distant sites. Several years of annual vegetation monitoring data indicated that PCB emissions increased prior to the reported accident. Within 3 km of the plant, there was a predominance of higher chlorinated congeners penta-, hexa-, hepta-, and octachlorobiphenyls in white spruce (Picea glauca) needles and snow. Polychlorinated biphenyl congener patterns varied seasonally in spruce needles, likely influenced by temperature effects on the volatilization and of particle-bound and vapor phase PCBs in the forest canopy. The similarity of deposition patterns in snow and needles in 1997 and 1998 suggested the PCBs in the surrounding area were derived by long-term fugitive releases of PCBs rather than an accidental release. In addition, hexachlorobenzene, a combustion by-product of chlorinated organics in waste incinerators, was not measured at elevated concentrations in spruce needles or snow east of the facility and, when detected, was not correlated with PCB concentrations. A radiometrically dated sediment core from nearby Chrystina Lake (AB, Canada) showed a gradual increase in annual PCB flux during the early years of operation of the ASWTC, followed by a higher PCB flux in 1997, indicating that the lake may have been directly contaminated by the accidental release.

Completeness and Validity of Cancer Registration in a Major Public Referral Hospital in Saudi Arabia

The 1994 Saudi National Cancer Registry (NCR), a population-based registry, showed a crude incidence rate (CIR) of 39/100,000 for all cancers in the Saudi population. The low CIR suggested possible under-reporting, especially during the early years of operation. This study as aimed at estimating the number of missed cases due to under-reporting, and to assess the validity of reported data from a major public referral hospital in Riyadh city. We compared cancer cases from the three data sources: medical records (MR), which were the original source of NCR cases; pathology reports (PR); and death certificates (DC). We estimated the missing cancer cases using the capture-recapture method with log-linear models of Fienberg to correct for interdependency between the three data sources. To assess the validity of the data, we reabstracted records of about 8% (39/4760 of previously reported cases from the same hospital. A total of 811 cancer cases were reported through the three sources, i.e., MR 611 (75.3%), PR 639 (78.8%) and DC 204 (25.2%). After fitting a series of log-linear models to the three sources of data, the three sources were found to be statistically dependent. Capture-repcapture method indicated that 384 cases were missed, giving an estimation of 1195 cancer cases to be reported. Using these 1195 estimated cases; the estimated ascertainment rates were 51% for medical records, 53% for pathology reports, 17% for death certificates, and 68% for the aggregated registry. In the validity assessment, major disagreement between the abstracted and reabstracted data was found to be highest for stage of disease (44%), followed by histology code and behavior (25.6%). Minor disagreements were most common for date of diagnosis (36%) and grade (36%). Overall, agreements were highest for laterality (95%), followed by primary site codes (90%) and basis of diagnosis (85%). Agreement of tumor description variables (site, histology, behavior, and stage) was 57%. Cancer registration will require substantial improvements in both completeness of reporting and data quality at the hospital level. Use of multiple data sources and estimation of missed cases will help ensure completeness of case registration.

A reappraisal of the reported dose equivalents at the boundary of the University of California Radiation Laboratory during the early days of Bevatron operation.

The Bevatron of the Lawrence Berkeley National Laboratory operated with no permanent shielding-roof from 1954 to 1962. Neutron fluences measured at the laboratory perimeter reached a maximum in 1959, and were reported as an annual dose equivalent of 8.1 mSv (54% of the then operative radiation limit). The addition of temporary local shielding and improved operational techniques subsequently led to a steady decline in dose equivalent at the laboratory perimeter. A permanent concrete shielding-roof was constructed in 1962. In those early years of operation the reported dose equivalent, H, was derived from a measured total neutron fluence, phi, and an estimated spectrum-weighted fluence to dose equivalent conversion coefficient, (g), where H= (g) phi. The uncertainty in H was almost entirely due to the uncertainty in (g). While the measurements of phi were accurate the estimates of (g) were quite crude and depended upon measurements of average neutron energy, on assumptions about the shape of the neutron energy spectrum, and primitive values of fluence to dose equivalent conversion coefficients for monoenergetic neutrons. These early reported dose equivalents were known to be overestimated. This paper has reappraised the dose equivalents in the light of better information now available. Environmental neutron spectra have been calculated which more accurately correspond to the operational conditions of the Bevatron in the 1950s and early 1960s. than did those spectra available at that time. A new fluence to dose equivalent conversion function based on the latest data and for isotropic irradiation geometry was developed. From these two parameters better estimates of the coefficient (g) were determined and compared with the earlier values. From this reappraisal it is shown that the early reported dose equivalents were conservative by a factor of at least five.

The changing pattern of reoperative coronary surgery: Trends in 1230 consecutive reoperations

Objective: We noted an increasing risk profile of patients undergoing reoperative coronary surgery. We evaluated the risk compared with primary procedures, our results over a 16-year span, and the predictors of hospital outcomes after redo surgery. Methods: We analyzed 20,614 patients undergoing isolated coronary surgery at our institution from 1982 to 1997. Of these, 1230 (6.0%) were undergoing reoperation. Independent predictors of outcomes were identified by multivariable regression. Results: The prevalence of reoperation peaked in 1994 at 8.2%. Patients undergoing reoperation were more likely to be male, to have left ventricular dysfunction and worse symptoms, and to require an urgent operation than patients undergoing a primary operation (P <.0001). Perioperative myocardial infarctions (3.7% vs 7.4%), low-output syndrome (9.0% vs 24.0%), and death (2.4% vs 6.8%) were more common in patients undergoing reoperation (all P <.0001). Over the years, the risk profile of patients undergoing reoperation increased. Age, left ventricular dysfunction, severity of symptoms, extent of coronary artery disease, left main stenosis, and requirement for urgent or emergency operations increased with time (P <.05). However, mortality, myocardial infarction, and low-output syndrome have remained constant. The independent predictors of mortality after reoperative surgery were increased age, greater Canadian Cardiovascular Society symptom class, earlier year of operation, and greater left ventricular dysfunction. After 1990, analysis of an expanded data set also identified peripheral vascular disease and failure to use retrograde cardioplegia as predictors of mortality. Conclusions: Improving results of reoperative surgery have been offset by an increasing patient risk profile. Meticulous operative technique and retrograde cardioplegia may permit good results in these high-risk patients. (J Thorac Cardiovasc Surg 2000;120:156-63)

Preliminary assessment of current radiation doses to the population of Brodokalmak from contamination of the Techa River

Significant quantities of liquid radioactive waste were discharged to the Techa River in the southern Urals region of Russia in the early years of operation of the Mayak PA plant (1948–1951). A collaborative project is underway under contract to the European Commission to consider the radiological impact of radioactive contamination in the Southern Urals. Part of this project involves the calculation of radiation doses currently received by the population of Brodokalmak on the Techa river. The assessment made use of local data on the habits of the population and measurements of radionuclide activity concentrations in food and water. Exposure pathways included in the assessment were ingestion of foods and external exposure to gamma radiation from radionuclides deposited on the banks of the river. A range of doses was calculated for different age groups, firstly, assuming that the restrictions in place are retained and, secondly, assuming that there are no restrictions. These restrictions include bans on drinking river water, fishing and bathing in the river and the prohibition of use of the river and surrounding flood plains by humans and cattle. With restrictions the highest dose estimated was 0.56 mSv y −1 for the most exposed adults and without restrictions this increased to 3.4 mSv y −1.

Russia enters the railway age, 1842-1855

Focuses on the planning, financing, construction, and early years of operation of the St. Petersburg-Moscow Railway, which was the largest single project undertaken by Peter the Great and a major departure point for further railway construction in Russia. The text pays special attention to the roles played by British and American engineers and entrepreneurs, the quality of Russian engineering skills, and the successes and failures in the transfer of foreign technology to Russia. The work should be of value to scholars studying the economic and industrial development of Russia, as well as anyone with an interest in the political and social history of pre-reform Russia.

Efficacy of the internal mammary artery in combined aortic valve replacement-coronary artery bypass grafting

Background. While internal mammary artery (IMA) use predicts improved survival after coronary bypass grafting (CABG), it remains unknown whether patients undergoing concomitant aortic valve replacement (AVR) realize a similar benefit.Methods. All patients at a single teaching institution, undergoing combined AVR-CABG, which included a graft to the left anterior descending coronary artery (LAD) from 1984 to 1994 (n = 227) were examined retrospectively.Results. Patients receiving an IMA graft (yesIMA, n = 135) and patients receiving only saphenous vein grafts (nonIMA, n = 92) were not different in their presenting symptoms, or in their incidence of preoperative risk factors. The patients with IMA were more likely to be male, have a later year of operation, be younger, and have a greater body surface. Morbidity was not different between groups. IMA use did not affect 30-day mortality. Long-term actuarial survival was greater in the group with IMA (63% ± 7% vs 42% ± 6% at 5 years, p< 0.01). A multivariate Cox proportional hazards model demonstrated that use of an IMA graft improved survival, while recent myocardial infarction, diabetes, earlier year of operation, and lower ejection fraction diminished long-term survival. The relative risk of IMA grafting was 0.570.Conclusions. Within the limits of a retrospective analysis, patients in a modern era of cardiac operation, who undergo combined AVR-CABG, do not suffer increased morbidity from IMA use, and may realize a survival benefit from use of the IMA as a conduit for bypass of the LAD coronary artery.

A 26-year experience with surgical management of tetralogy of fallot: risk analysis for mortality or late reintervention

Background. Over the past decade repair of tetralogy of Fallot (TOF) in infancy has gained favor. It is still uncertain what effect early complete repair will have on survival or late reoperation on the right ventricular outflow tract. Methods. To assess these outcomes, we reviewed our experience (1971–1997) with 294 patients undergoing operation at one institution. Median follow-up was 10.6 years (range, 0.1 to 26 years), and was complete for 90.2% patients. Results. Primary complete repair was done in 199 patients (68%), and a staged repair in 62 patients (21%). Thirty-three patients had only a palliative procedure. Sixty-eight patients (23.1%) had complex pathologic processes, including pulmonary atresia in 53. Hospital mortality for primary repair was 11.1% (22/199), for staged repair was 17.7% (11/62), and for palliative procedures was 15.5% (16/103 procedures). Since 1990 mortality has been 2.1%, 11.8%, and 0% respectively ( p < 0.001), despite younger age at repair (0.6 ± 0.1 versus 2.1 ± 0.2 years; p < 0.001). Multivariate analysis identified longer period of hypothermic circulatory arrest, pulmonary artery patch angioplasty, earlier year of operation, and closure of the foramen ovale as risk factors for hospital death. For hospital survivors 20-year survival was 98% ± 3% for TOF with pulmonary stenosis and 88% ± 9% for TOF with pulmonary atresia ( p = 0.09). Reintervention on the right ventricular outflow tract was needed in 14.1% (37/261) patients. Freedom from reintervention on the right ventricular outflow tract at 20 years was 86% ± 4% for TOF with pulmonary stenosis and 43% ± 16% for TOF with pulmonary atresia ( p = 0.001). For the subgroup TOF with pulmonary stenosis, this was 85% ± 5% after primary repair and 91% ± 8% after staged repair (not significant). At 15-year follow-up, this was 78% ± 10% for patients not older than 1 year at operation compared with 88% ± 4% for older patients (not significant). Conclusions. Early mortality after primary repair of TOF has significantly improved and late survival is excellent. Primary repair in infancy does not increase risk for reintervention on the right ventricular outflow tract.

Cancer incidence in Ho Chi Minh City, Viet Nam, 1995-1996.

The results from the population-based cancer registry for the city of Ho Chi Minh in 1995-1996 represent the first information on the incidence of cancer in southern Viet Nam. A total of 4,080 cancer cases in males and 4,338 in females were registered, corresponding to age-standardized incidence rates (ASRs) of 130.9 per 100,000 in men and 100.7 per 100,000 in women. As elsewhere in South East Asia, the principal cancer of men was liver cancer (ASR 25.3), with moderately high rates of lung cancer (ASR 24.6) and stomach cancer (ASR 16.5); cancer of the penis, reportedly very common in early case series from Viet Nam, is now rarely seen. In women, cervical cancer was the dominant malignancy (ASR 26.0) followed by breast cancer (ASR 12.2) and stomach cancer (ASR 7.5). Although there may be some under-registration in these early years of operation, the recorded rates of cervical cancer and liver cancer are already high and suggest that southern Viet Nam would benefit from an effective cervical cancer screening programme, as well as efforts to interrupt the transmission of hepatitis B virus to reduce liver cancer incidence and effective anti-smoking programs.

Survival patterns among newcomers to franchising

This study examines survival patterns among franchisee and nonfranchise small firms and establishments that entered business during 1986 and 1987. Aspiring entrepreneurs purchasing franchises choose this path to small business entry, in part, because they expect to improve their chances of survival during the turbulent early years of operation. Evidence to date has been mixed: some studies conclude that franchising is a low-risk route to small business ownership, while others suggest that independent start-ups are more likely to remain in operation than franchises. This study utilizes two distinct methodological approaches to investigate franchisee survival patterns. The first approach demonstrates that franchise units have better survival prospects than independents, and the second approach demonstrates that young firms formed without the benefit of a franchisor parent are more likely to remain in operation than franchised start-ups. Reconciliation of these seemingly inconsistent findings is explored. Survival measurement is heavily influenced by the unit of analysis in franchising. Firm-specific data show different patterns than establishment-specific data when young franchise units are tracked through time. Analysis of establishments owned by corporations is undertaken for restaurants opened nationwide in 1986 and 1987. Using Census Bureau data describing corporate-owned restaurant establishments that reported payroll to the IRS in 1987, 52,088 young establishments were identified; 22.5% were franchises. Comparison of the franchisee and independent restaurant units indicated that independents were more likely to cease operations by 1988 than franchises. The fact that franchisee establishments had a better survival track record than independent restaurants does not, however, demonstrate that aspiring entrepreneurs improve their survival prospects by purchasing a franchise. In fact, 84% of the new franchise establishments under consideration were units of multi-establishment corporations, and few of these corporate parents were new businesses. Envision a corporation in operation for 15 years that owns 20 McDonalds restaurants; in 1987 they opened their twenty-first unit. The findings of this study indicate that this twenty-first unit has excellent survival prospects, more so than either an independent start-up or a franchisee opening a restaurant for the first time. New franchised restaurant units, overall, may be a safe investment, although simultaneously, the newcomer opening a franchise may face a high-risk situation. The analysis then shifts from establishments owned by franchisees to young firms (not establishments) started in 1986 and 1987 as proprietorships, partnerships, or S-corporations. Among these young firms, franchisees are found to have lower survival rates than independent start-ups, and these differences persist when various firm and owner traits are controlled for statistically. Retailing is found to be a particularly difficult field for young franchised firms: risk of firm closure is high and mean profits are negative. The most common route into retailing entailed purchasing an operating franchise unit from its previous owner, that is, an ongoing franchise. Over 53% of the young franchised retailing firms started in 1986 and 1987 were ongoing operations. By 1991, only 52.4% of these firms were still operating with the owner of record present in 1987. The findings of this study indicate, on balance, that purchase of a franchise is unlikely to reduce the risks facing a new business start-up. This does not imply that the multi-establishment franchisee adding another new franchise unit to its existing chain of operations faces a high-risk situation. Rather, the high risk facing the franchisee newcomer is partially rooted in the fact that so many of the newly-opened units in mature franchising niches are owned by multi-unit franchisees that have greater experience and resources than newcomers who are attempting to enter the industry.

Deposition of actinides in the vicinity of Sellafield, Cumbria: Accounting for historical discharges to atmosphere from the plant

Soil core samples from 95 locations within a few kilometres of the Sellafield nuclear complex have been used to assess the cumulative deposition of 238Pu, 239,240Pu, 241Pu and 241Am in the vicinity of the plant. The deposition pattern is characterised by high levels of 239,240Pu (up to 20 000 Bq m−2) within a few hundred metres of the site, declining rapidly to much lower levels (∼1000 Bq m−2) within 3 km. The activity ratio of 238Pu to 239,240Pu associated with the highest levels of deposition is in the range 0.02–0.05, indicating that the plutonium originated from uranium of low irradiation and suggesting that the deposition occurred during the early years of operation of the plant. 241Am deposition levels correlate strongly with 239,240Pu and the average activity ratio of 241Am to 239,240Pu, at 0.2, is consistent with ingrowth from deposited 241Pu. Deposition of 238Pu and 239,240Pu at distances >2 km from the plant is consistent with that calculated from the cumulative recorded emissions to atmosphere from the plant, together with sea to land transfer and weapons testing fallout. To explain the high levels of deposition close to the site, it is necessary to assume an additional cumulative release of ∼70 GBq with a high deposition velocity. The spatial pattern of deposition indicates that some of this additional release is associated with a known incident involving the Calder cooling towers in 1961; a further source in the northern part of the chemical separation area is also indicated.

Surgical management of aortic dissection during a 30-year period.

Certain recent studies have demonstrated improved surgical outcome in patients with aortic dissection. We analyzed the surgical survival rates of patients with acute aortic dissections and the late prognosis of those with aortic dissection during a 30-year period. Between 1963 and 1992, 360 patients (256 men and 104 women; mean +/- 1 SD age, 57 +/- 14 years) underwent surgery for aortic dissection: 174 patients had an acute type A (AcA), 46 an acute type B (AcB), 106 a chronic type A (ChA), and 34 a chronic type B (ChB) aortic dissection. The overall operative mortality rate was 24 +/- 8% (26 +/- 3% for AcA, 39 +/- 8% for AcB, 17 +/- 4% for ChA, and 15 +/- 6% for ChB, [+/- 70% confidence limit]). The operative mortality rates for patients with acute aortic dissection (AcA or AcB) were assessed for five time "windows": 1963 to 1972 (42 +/- 8%), 1973 to 1977 (37 +/- 8%), 1978 to 1982 (15 +/- 6%), 1983 to 1987 (27 +/- 6%), and 1988 to 1992 (26 +/- 6%). Logistic regression analysis suggested that the low operative mortality rate during the 1978-to-1982 interval occurred by chance. Multivariate analysis showed earlier operative year, hypertension, cardiac tamponade, renal dysfunction, and older age were independent determinants of operative death. Actuarial survival rates (including early deaths) after 5, 10, and 15 years for AcA patients were 55%, 37%, and 24%; for AcB, 48%, 29%, and 11%; for ChA, 65%, 45%, and 27%; and for ChB, 59%, 45%, and 27%. Multivariate analysis revealed that older age and previous operation were significant predictors for late death. Freedom from reoperation for all patients was 84%, 67%, and 57% at 5, 10, and 15 years, respectively. Although the operative mortality rate decreased over time for patients with aortic dissection, the risk for those with acute aortic dissection during the last 10 years (1983 to 1992) is probably more realistic than that observed in the preceding 5-year interval (1978 to 1982). The operative mortality rates for patients with chronic aortic dissection have remained relatively static. Earlier diagnosis of acute aortic dissection before development of cardiac tamponade and renal impairment is critical to improve the operative salvage rate. Long-term outcome still is not optimal, which emphasizes the need for better serial postoperative aortic imaging surveillance and medical follow-up and blood pressure control.

Voluntary Organizations in Developing Countries and Colonial Societies: The Social Service Department of the Palestine Jewish Community in the 1930s

Voluntary organizations may serve somewhat different functions in devel oping countries and colonial societies than they do in more developed countries. In all societies, voluntary organizations engage in social action in order to make their governments more responsive to the social needs and political rights of the population, but this function is especially crucial in societies where there is no access to the political decision-making structures. This case study explores yet another role for the voluntary organization: the deliberate and planful utilization of a voluntary organi zation structure to prepare for self-government and political independence. The establishment and early years of operation of the Social Service Department of the Jewish National Council in British-ruled Palestine in the 1930s serves as the example.

Prognostic factors for surgically treated lung adenocarcinoma patients, with special reference to smoking habit.

Prognostic factors for lung adenocarcinoma patients who had been treated surgically at the Center for Adult Diseases, Osaka, in 1978–87 (N = 267) were analyzed In terms of year of operation, sex, age at operation, postsurgical stage, grade of differentiation, and smoking habit. Survival was improved for later year of operation (1983–87), younger age at operation, stage I or II, well or moderately differentiated adenocarcinoma, and nonsmoking status in univariate analysis. A proportional hazards model including the above variables showed that stage III and stage IV patients had 4.06 and 8.81 times higher risk of death compared to stage I and II patients. Poorly differentiated adenocarcinoma showed 2.01 times higher risk of death than well or moderately differentiated adenocarcinoma. Earlier year of operation and female status showed 1.70 and 1.82 times higher risk of death, respectively, as compared to each reference group. All these hazard ratios showed statistical significance. Current smokers who smoked 1,000 or more on the cigarette index showed 2.38 times higher risk of death than nonsmokers with statistical significance. This indicates that smoking is another independent prognostic factor for patients who undergo operations for adenocarcinoma of the lung.